Prior to this invention, the applicant of this invention filed an application for patent (See patent document 1). That invention related to a discharge container comprising a squeezable container having an outer layer, an inner layer laminated with the outer layer in a manner that the inner layer is peelable from the outer layer, a container neck disposed on top of this squeezable container and used to form a discharge port for the contents, and an opening disposed in a part of the outer layer located in the bottom plate of bottom cylinder and used to introduce outside air into the interspace between the outer layer and the inner layer; and also comprising the first check valve used to open or close the neck of the squeezable container so as to prevent the backflow of the contents into the container and the inflow of outside air, a base cup tightly fitted around the bottom cylinder and having an air intake hole disposed in the cup bottom plate, and the second check valve fitted to the air intake hole of the base cup to permit outside air to pass through the air intake hole.
[Patent document 1] P2002-129195 patent specification
In the above-described conventional art, the container bottom has stable strength and a self-standing function because the base cup serves to reinforce the container bottom. However, if the squeezability of the container is enhanced in response to an increasing request for resources saving, the container tends to be much more deformable. Depending on the extent of deformability, there is a fear that the firm fitting strength and reliable sealing property may decrease between the container and the base cup.